Purpose: The effect of sedentary behavior on regional fat deposition, independent of physical activity, remains equivocal. We examined the cross-sectional associations between objectively measured sedentary time and markers of regional fat distribution (heart, liver, visceral, subcutaneous, and total body fat) in a population at a high risk of type 2 diabetes mellitus (T2DM).
Methods: Participants were recruited from primary care to two diabetes prevention programs. Sedentary time (<25 counts per 15 s) was measured using ActiGraph GT3X accelerometers. Heart, liver, visceral, subcutaneous, and total body fat were quantified using magnetic resonance images. Fat volumes were calculated by multiplying the cross-sectional areas of the fat-containing pixels by the slice thickness. The liver fat percentage was measured using a representative region of interest created in the right lobe of the liver, avoiding the main portal veins. Linear regression models examined the association of sedentary time with markers of regional fat deposition.
Results: Sixty-six participants (age, 47.9 ± 16.2 yr; male, 50.0%) were included. After adjustment for several covariates, including glycemia, whole-body fat, and moderate-to-vigorous physical activity, each 30 min of sedentary time was associated with 15.7 cm3 higher heart fat (P = 0.008), 1.2% higher liver fat (P = 0.026), and 183.7 cm3 higher visceral fat (P = 0.039).
Conclusions: This study provides new evidence suggesting that objectively measured sedentary behavior may have an independent association with heart, liver, and visceral fat in individuals at a high risk of T2DM.
1National Institute for Health Research Leicester–Loughborough Diet, Lifestyle, and Physical Activity Biomedical Research Unit, and Diabetes Research Centre, College of Medicine, Biological Sciences and Psychology, Leicester, UNITED KINGDOM; 2Department of Cancer Studies and Molecular Medicine, College of Medicine, Biological Sciences and Psychology, University of Leicester, Leicester, UNITED KINGDOM; 3Department of Cardiovascular Sciences, College of Medicine, Biological Sciences and Psychology, University of Leicester, Leicester, UNITED KINGDOM; 4Institute of Sport, Exercise & Active Living, Victoria University, Melbourne, AUSTRALIA; 5School of Sport, University of Stirling, Stirling, UNITED KINGDOM; 6College of Life and Environmental Sciences, University of Birmingham, Birmingham, UNITED KINGDOM; 7Department of Cardiovascular Sciences, University of Leicester and the National Institute for Health Research Leicester Cardiovascular Biomedical Research Unit, Leicester, UNITED KINGDOM; 8National Institute for Health Research Collaborations for Leadership in Applied Health Research and Care East Midlands, and Diabetes Research Centre, College of Medicine, Biological Sciences and Psychology, University of Leicester, Leicester, UNITED KINGDOM
Address for correspondence: Charlotte Edwardson, Ph.D., Diabetes Research Centre, College of Medicine, Biological Sciences and Psychology, University of Leicester, Leicester General Hospital, Leicester, LE5 4PW United Kingdom; E-mail: email@example.com.
Submitted for publication September 2014.
Accepted for publication November 2014.
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